This invention relates generally to a tool used to remove compressed rings from tubing joints. More specifically, this tool relates to the removal of crimped rings used to secure plastic plumbing pipe or tubing over a fitting.
The introduction of plastic plumbing to the construction industry has resulted in a significant saving of time. The conduit used in plastic plumbing is referred by a variety of terms such as hose, piping or tubing. Steel piping requires a labor and time intensive fitting and threading process. Rigid copper piping avoids the threading process but replaces it with the need for soldering. Plastic tubing requires less fitting and the resulting joints are easy to complete. Tubing used for household plumbing is placed over a fitting""s barbed or ribbed nipple and secured with a clamp of some sort.
It is known to crimp rings, such as annealed copper rings, over plastic plumbing tubing attached to the fitting""s nipples, in order to provide a more secure joint. The tubing is resilient and is caused to deform over the ribs of the rigid nipple, preventing the tubing""s removal therefrom. A number of tools have been developed to crimp the ring over the tubing and the nipple. One such tool is described in U.S. Pat. No. 5,289,712 to Haughian, wherein a lever type tool is used to apply pressure and reduce the diameter of the ring over the tubing, once positioned over a ribbed nipple. The tubing under the ring is permanently deformed.
Sometimes it is necessary to change the connection at the joint, to correct an error, alter the configuration, or merely to remove the fitting. Preferably the fitting is salvaged for reuse, due in part to economics but also to avoid the need to change all other joints on the affected fitting. Due to the deformation of the tubing at the old joint, the deformed part is usually cut off.
To change the joint, the crimped ring is removed before the tubing can be removed from the ribbed nipple. Currently, removal of these crimped rings presents a challenge, as most plumbers are forced to use a hacksaw to angle cut the ring from the tubing and the nipple. This may result in damage to the nipple as it is difficult to visualize the point at which the ring has been cut and the underlying nipple has not. The tubing offers little resistance to the hacksaw and one can cut through the tubing and into the nipple with little warning. Further, joints of this type are often too closely spaced or are located in areas with little space to maneuver a saw.
There are a number of tools used to hold and cut pipe or tubing, such as described in U.S. Pat. No. 287,378 to Herbert and U.S. Pat. No. 198,709 to Thornton. Generally, these pipe-cutting devices cut the pipe circumferentially. U.S. Pat. No. 45,496 describes a device which has a nearly tangential pipe thread cutting tooth. None of these tools could be used to remove a crimp ring from tubing. Further, tools which would apply a force perpendicular to the surface of the ring could result in deformation or damage to the fitting.
There is clearly a demonstrated need for a tool that can remove a crimped ring without damaging the underlying nipple and which is simple and easy to operate under a variety of conditions.
In a preferred embodiment, a device is provided for removing an annular ring from plastic tubing overlying a plumbing fitting. The device has the advantages of simplicity, ease of operation and does not risk injury to the fitting. In an embodiment implementing pivoting jaws and handles, the jaws are placed over the crimped ring and actuation of the handles allows one jaw to support the ring while the other cuts the ring on a path tangent to the inside circumference of the ring which thereby avoids injuring the fitting.
In a broad aspect then, apparatus is provided for cutting a crimped ring from an underlying cylindrical object, such as plastic tubing overlying a nipple, the apparatus comprising an annular recess for radially supporting at least a portion of the ring along its circumference and a ring-cutting chisel. Means are provided for actuating the chisel between resting and ring-cutting positions, preferably being a pair of pivoting levers, which form the recess and chisel portions. The chisel, when actuated from a resting position to a cutting position, engages and cuts through the ring across its width and along a path substantially tangent to the ring""s inner circumference so as to leave the underlying circular object intact, the ring being supported by the annular recess.
Preferably, the actuating means are a pair of levers or a screw actuated chisel integrated into a unitary body. More preferably, serrations can be provided in the annular recess to prevent rotation of the ring while cutting.